Turbine engines have one or more circular arrays of stationary vanes that direct a working gas against corresponding circular arrays of rotating blades. A vane is an airfoil attached at each end to a platform member. This attachment must be strong enough to support cantilever and rotational forces on the vane exerted by the working gas. One assembly method is to cast one or more vanes integrally between inner and outer platform members to form what is called a vane segment or nozzle segment. However, such an integral assembly cannot be disassembled for service. Reversible joining methods are preferred for disassembly and replacement of sub-component pieces for repair or replacement. Threaded bolts and nuts can be used to attach vanes to platforms and allow disassembly. However, threaded fasteners can loosen during operational vibrations. Pin-type fasteners can be used, but they do not draw the vane against the platform, which is desirable to resist shifting and to prevent vibration. Pins and other mechanical fasteners may require precisely machined mating surfaces, yet they still may vibrate, shift, or loosen during service.
U.S. Patent Application Publication US 2005/0254942 A1 of the present assignee teaches a joining method for assembling components in which a first ceramic matrix composite (CMC) component is fabricated and fired to a selected first cured state. A second CMC element is fabricated and left in a green state, or is fired to a second partially cured state less complete than that of the first cured state. The two CMC elements are joined in a mating interface, and are then fired together, resulting in differential shrinkage that compresses the outer joining portion on the inner joining portion, locking them together. This mechanism and method is useful for securing the end of a vane in place relative to a platform element after the two pieces are urged together by another mechanism.